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Thread: Can an A coil be repaired?
07-24-2009, 10:39 AM #1
Can an A coil be repaired?
Guys, I have 5 year old never installed Goodman 5 ton ac unit. I found a hole in the A coil...can this be silvered soldered. I know I'll have to remove some of the aluminum fins around the nicked copper tube. I'm pretty good at silver soldering. I will post a pic on Saturday. The local Goodman ac guys want to service AND sell parts....won't just sell me the coil.
07-24-2009, 10:46 AM #2
I would say yes. I don't know of any reason why you couldn't do this. I have soldered many a tractor radiator and have never had a problem. I know this is somewhat different but not much. Just cut the fins away and solder it.
07-24-2009, 11:03 AM #3
What type of pressures does a condinser coil see? I would think it is pretty high, still I would think a small hole could be easily repaired. You could take some copper (1" section maybe) of the same size, slit it down one side and snap it over the damaged area. Silver solder, relying on capillary action to pull you silver solder evenly around. I would think this would be plenty resilient.
07-24-2009, 11:32 AM #4
No problem I can foresee, jobs like that though not pressure vessels I test afterwards by pressurising with compressed air and immersing in water, you got a leak that'll find it
07-24-2009, 04:22 PM #5
I go with #3 above. making a 1/2 round patch to fit tightly over the nick would get away from having an almost full round not wanting to snug up.
The tubes and fittings are brazed together, silver soldering is at least as strong as brazing, so you should have no problem.
If you are installing it yourself, pull a vacuum, close all the valves, and note the gauge, let it sit overnight and see if you have lost any. Or pressurize to 150 pounds, and do as above.
The A coil in the air handler/furnace works at the low side pressure, the one outside that cools the compressed gas will work at the high side pressure. Those numbers are usually on the compressor housing.
Not good to lose the freon in a short time.
07-25-2009, 01:37 PM #6
Here's a picture of the A coil. The copper tubing is around .500 in dia.
07-25-2009, 10:31 PM #7
a/c guy here.
Just get some silphos 15% from goodman and just solder it. You don't really even have to clean it. Cut the fins out of your way though.
This will hold up Justttttt fine.
07-25-2009, 11:31 PM #8
Sure it can, common practice in commercial AC, either the line is bypassed or the hole is covered with silver solder as mentioned before 15% is good, common in any AC or plumbers supplies. I have even seen a length of smaller tube slipped inside the entire length of a damaged tube and this was a 20ft long coil.
The repair will look ugly as the aluminium fins around the repair will melt but so what as long as it cools.
07-26-2009, 07:53 AM #9
That looks like an evaporator coil. Not a lot of pressure on it. Been there done it. I would just clean it up well, flux it, and lead (tin now) solder it. Wouldn't even need to cut away the fins. It should hold just fine. I don't see a need to silver solder it. Evacuate the system and recharge it. Should last as long as the unit.
07-26-2009, 08:27 AM #10
Grind the point off that sheet metal screw before you work, or back it out, out of the way. Besides the strong and weak forces described by modern physics, a third type of force - inevitable - causes attraction between sharp screw points and soft flesh.
07-26-2009, 03:02 PM #11
I'd spend 10 minutes cleaning and 10 seconds silver brazing it, 15-56% silver will work fine. The mfg would probably say to inert braze it, 1-2 psi of nitrogen in the coil while working but if you don't have a tank of nitrogen don't worry about it.
Most important step in the repair is a deep evacuation afterwards, extra emphasis on this.